摘要
人工地面甚低频台站发射的10-30 kHz信号主要在地球-低电离层波导传播,部分能量会泄露进入内磁层,进而会影响近地空间中高能电子的动态变化过程.本文详细研究了NWC,NAA和DHO38三个人工甚低频台站信号对内辐射带和槽区高能电子的散射作用.基于准线性理论,分别计算了三个甚低频台站信号单独和共同作用时对高能电子的弹跳平均投掷角扩散系数,并进一步利用Fokker-Planck扩散方程模拟内辐射带及槽区的高能电子在200 d内的动态演化过程.结果表明,在低L-shell(L≤1.8),NWC台站信号对电子的损失占主导作用,可以使能量在100 keV附近、投掷角小于60°的电子出现明显损失;在较高的L-shell(2.2≤L≤2.7),主要是NAA和DHO38台站信号占主导作用,可以使能量小于20 keV、投掷角小于70°的电子通量显著下降;三个甚低频台站信号对高投掷角(>80°)的电子均无显著影响.
Whistler mode very low frequency(VLF)waves from man-made ground-based transmitters in a frequency range of 10–30 kHz are mainly used for submarine communication,and they propagate primarily in the Earth-lower ionosphere waveguide and part of their energy can leak into the inner magnetosphere,leading the energetic electrons in inner radiation belt and slot region to precipitate into atmosphere and then affect the energetic electron dynamics in the near-Earth space.The scattering effects of artificial VLF signals from NWC,NAA and DHO38 transmitters on energetic electrons in Earth’s inner belt and slot region are investigated in detail in this work.Based on the quasi-linear theory and the Full Diffusion Code,we calculate the bounce-average pitch angle diffusion coefficients induced by NWC,NAA and DHO38 VLF transmitter signals,for which the resonance harmonics|N|≤10 are considered,respectively.We further implement the one-dimensional Fokker-Planck diffusion simulations by using the available pitch angle diffusion rates to model the dynamic evolutions of energetic electrons caused by the scattering of the VLF transmitter signals in the inner belt and slot region in 200 d.The simulation results indicate that the NWC VLF transmitter signals are dominant in scattering~100 keV electrons with pitch angles less than 60°at L≤1.8,and the mainly scattered electron energy values increase with L-shell decreasing,from L=1.8 to L=1.5,the mainly scattered electron energy increases from 90–120 keV to 550–650 keV.The NAA and DHO38 VLF transmitter signals are important in scattering<20 keV electrons with pitch angles less than 70°at higher L-shells(2.2≤L≤2.7),from L=2.2 to L=2.7,the mainly scattered electron energy decreases from 10–20 keV to several keV.The VLF transmitter signals are found to have a slight influence on the loss of energetic electrons with pitch angles larger than 80°.
作者
刘阳希子
项正
郭建广
顾旭东
付松
周若贤
花漫
朱琪
易娟
倪彬彬
Liu Yang-Xi-Zi;Xiang Zheng;Guo Jian-Guang;Gu Xu-Dong;Fu Song;Zhou Ruo-Xian;Hua Man;Zhu Qi;Yi Juan;Ni Bin-Bin(Department of Space Physics,School of Electronic Information,Wuhan University,Wuhan 430072,China;Key Laboratory of Space Weather,National Center for Space Weather,China Meteorological Administration,Beijing 100081,China;Center for Excellence in Comparative Planetology,Chinese Academy of Sciences,Hefei 230026,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第14期399-409,共11页
Acta Physica Sinica
基金
国家自然科学基金(批准号:42025404,41704162,41974186,41674163,41904144,41904143)
中国科学院先导B计划(批准号:XDB41000000)
国家航天局民用航天预研项目(批准号:D020303,D020308,D020104)
中国博士后科学基金(批准号:2019M662700)资助的课题.
关键词
地球辐射带
人工甚低频台站信号
波粒相互作用
电子投掷角扩散系数
Earth’s radiation belts
artificial very low frequency transmitter signals
wave-particle interactions
electron pitch angle diffusion coefficient
